There are some environmental factors that have negative effects on IQ. Three I will touch on today are nutrition, disease and parasitic load. All three mean decreased cognitive ability as well as a slew of other negative effects on their lifestyle.
To start, nutrition of the mother is one of the most important and telling things for the health as well as IQ of the child. Prenatal nutrition is very important to a developing fetus. What the mother eats has a big effect on the fetus. For instance, vitamins and minerals are extremely important. A pregnant mother needs two times the amount of folic acid than a non-pregnant mother. A pregnant woman needs 400 mcg per day to prevent defects to the babies brain and spine called neural tube defects. A pregnant woman also needs double the amount of iron than a non-pregnant woman.
We can see here that if a pregnant woman is protein deficient, it passes on to the baby. Protein is more important in the second and third trimester due to the fetus developing more rapidly. It can also lead to growth retardation, due to reduced nutrient supply to the fetus. The authors end up concluding that the women who ingested 50-70 grams of protein per day and 156 to 465 ml of milk had children with significant and better tendency in femur length, bi-parietal diameter, abdomen circumference and head circumference. It’s important for a mother to get the right amount of protein for optimal fetal growth.
It’s also known how malnutrition in early years can lead to antisocial and aggressive behavior as well as lower cognition. It’s due to what I touched on above. They state that malnutrition in early childhood years such as lack of iron, zinc, B vitamins as well as being protein deficient leads to the 3 aforementioned things. As I have shown in the previous paragraph, the lack of the same nutrients during fetal development causes the same problems.
Now that I have touched on how prenatal nutrition is important for the fetus, I will talk about parasitic load.
According to a paper by Eppig et al, the prevalence of parasites is the cause of worldwide differences in cognitive ability. They state that from an energetics standpoint, that a developing human would have a hard time developing a brain while fighting infectious disease, as both are very metabolically demanding. They go through all of the theories of differences in cognitive ability, such as the cold winter hypothesis of Lynn, Rushton and Kanazawa, to studies of inbreeding depression by Saadat and Woodley. They state that Lynn has argued that nutrition is important to high degrees of mental development, that nutrition is the cause of the ‘Flynn Effect’ and that he showed that undernourished children have smaller heads, smaller brains and lower cognitive function than adequately nourished children. They end up concluding that as nations develop, they should be monitored for a decrease in parasitic infection to see if it correlates with a rise in IQ and whether any gain would be able to account for the ‘Flynn Effect’ (which the rate is 3 points per decade, no matter what population you look at).
To touch quickly on what Lynn said about undernourished children having smaller heads, smaller brains, and, therefore, lower cognitive function, all 3 of those variables are related. Brain size is correlated with cognitive ability at .44. So, we can see there is a pretty good relationship with brain size and IQ. So, those who don’t get adequate nutrition will, in turn, have a smaller head size and a smaller brain, which both lead to depressed intelligence.
There is evidence that Sickle Cell Anemia leads to a decrease in IQ. The authors conclude with MRI scans, that those with SCA have a decrease in total brain volume, which of course has a negative effect on cognitive ability. Though, that happened due to an increase in age. It’s known that brain size and the amount of neurons in the brain decrease with age. I won’t discount that SCA lowers cognitive ability, it’s a good hypothesis, along with the paper by Eppig et al, but I still think that Rushton, Lynn and Kanazawa’s Cold Winter Theory is the best evolutionary model for differences in intelligence found across the globe.
In the map above you can see the rate of malaria in the world. It’s concentrated around the equator as mosquitoes are the main transmitters of the parasites. Though, is it the parasitic load that causes low IQ or evolution in hot climates, which lead to low IQ and, in turn, makes them able to not be able to figure out how to cure the diseases due to low intellect? I believe it’s both, leaning more to the side of evolution in hot climate obviously, but I won’t discount that malaria, and therefore, SCA, has something to do with lower cognitive ability in those populations with higher rates of malaria.
So with all of the above factors, let’s talk about Africa.
We know they have the lowest IQs in the world (IQ 67 to 70), and we know they have the highest rates of malaria in the world, and also some of the worst nutritional standards of any geographic region in the world.
What is the cause? IQ? Disease? Parasitic load? Nutrient deficiencies?
All of the above. The last 3 are environmental effects that retard IQ. IQ drives most all development for a country, so with the last 3 points being there, obviously since they retard IQ, the QoL in the country will suffer.
Lynn states that with better nutrition that Africans will be able to reach their phenotypic IQ of 80. There is some good evidence for his claim as he also states that blacks with low to no white admixture have an IQ of 80. Rushton and Jensen also say that since psychologists don’t venture into the lowest income neighborhoods in the South, that the black IQ may be 78 in America, and not 85. Right there by the African phenotypic IQ of 80. So, that would mean that those with the highest amount of African ancestry have an IQ of around 80, plus or minus a few points. So if those African-Americans with low amount of white admixture have an IQ of 80, then it’s a good bet to take that if Africans themselves had proper nutrition that they would hit 80 as well, just as Lynn has stated.
Satoshi Kanazawa also said this back in 2006. Of course the media made him out to be someone who just said that without any backing of his claims. He compared IQ scores with indicators of ill health in 126 countries. He found that those countries with the lowest IQs have higher rates ill health. They accuse him of attempting to ‘revive the politics of eugenics by publishing the research which concludes that low IQ levels, rather than poverty and disease, are the reason why life expectancy is low and infant mortality high’. We know that poverty goes out the window because of the relationship between IQ and poverty. But as seen above, disease does have an effect on IQ. They only threw buzzwords at him and, of course, didn’t attempt to say anything meaningful to him.
The link between life expectancy and IQ is well studied. Those with lower IQs live shorter lives and those with higher IQs live longer lives. The studies and information I cite in that article corroborate what Kanazawa says about IQ and ability to fight disease.
IQ is affected by environmental factors such as disease, nutrition and parasitic load. I have given good evidence that with better nutrition, Africans can reach their phenotypic IQ of 80. But, they can’t learn how to farm because of their low IQ. They can’t get a higher IQ because they can’t learn how to farm.
The cause of this is evolution. When they say, as seen in Kanazawa’s article, that poverty (malnutrition) and disease are the causes of low IQ, low IQ causes those 2 things because those with lower IQ don’t have the abstract ability to think into the future that what they’re doing to their bodies can and will have negative effects in the future, which leads to decreased life span as I have noted in the article I have linked. It also leads to them not being able to farm, due to not having a high enough intellect due to evolving in the hot climates of the sub-Saharan desert. The only thing that holds wight, in my opinion, for the case for an environmental effect for lowered IQ is the case for parasitic load. So, I posit that if Africans were to some how to get it in to shape on their own and take care of those things on their own, they will be able to reach their phenotypic IQ of 80. We also know that immigrants from European countries with lower IQs, their descendants in America have IQs closer to average to the white average (100). 33 million people in Europe are at risk for malnutrition, so those who do come to America who are at risk for malnutrition, get the IQ boost due to living in America with better nutrition. This is also supported by African immigrants to America having a higher rate of collegiate attainment than white Americans, though that may be due to super-selection, only the smartest African populations coming here.
In conclusion, those African-Americans with low to no white admixture have an IQ of around 80, so it’s well supported that, with better nutrition, lower parasitic load and lower disease rate, Africans, and all other low IQ countries for that matter, can get a boost of around 10 to 15 points with all 3 things I have noted in this article taken care of.